When a display device integrates an antenna for short-distance or small-distance wireless communications, e.g. an NFC antenna, problems arise with the integration of this antenna concerning the discomfort caused to a user seeking to view displayed information as well as with the very performance of the antenna.
Thus, a first known approach to integrating an NFC antenna without causing discomfort to a user wanting to view information displayed on the display device consists in placing the antenna behind the display screen of the device in question. However, it can be seen that the working of the screen and of the corresponding electronics disturbs and/or absorbs the communications between transmitter and receiver, thus impairing the quality of the NFC link.
Another known approach consists in disposing the antenna on the rim of the screen of the display device. However, the goal often sought when integrating such a short-distance or small-distance wireless communications technology distance is often that the user should be able to access a piece of information by placing his terminal (for example his smartphone) at a specific position on the display screen, this position possibly depending on the content displayed. When the size of the screen increases, it is then difficult or even impossible to ensure a uniformity of a field on the entire surface of the display screen through an antenna disposed on the rim of this screen. More particularly, from a certain screen size onwards, the magnetic field collapses at the center of the screen.
Besides, attempts have been made to obtain conductive materials that enable the manufacture of transparent radiant elements that can be disposed directly on the display screen. Such materials are for example indium oxide, graphene or copper nanomesh. However, it appears that the conductors obtained are far too resistive to envisage a realistic implementation of the antenna. The fact is that, since the field generated is proportional to the current flowing in the antenna, extremely high power (or a very high voltage) is needed to obtain the desired field value which is not always compatible with the working of integrated circuits dedicated to NFC-type short-distance or small-distance wireless communications.
There is thus a need for an antenna that minimizes the discomfort caused to a user looking at information presented on a display device into which the antenna in question is integrated.
It is also necessary that the radiofrequency link between the antenna in question and the transmission/receiver with which it communicates should be unimpaired when the antenna is integrated into the display device.
There is also a need for these goals to be achieved independently of the size of the screen of the display device.